I have a few Rackable boxes now in our normally cooled data center. They are used as high density storage servers so they have a lot of disk drives, but they loose drives at a much higher rate than our other Dell and Supermicro based clones. You have to tread lightly around them because the slightest vibration will cause them to reboot. Yes they are properly mounted, etc.

Rackable == cheaply made

This page has a list of MySQL gotchas

http://sql-info.de/mysql/gotchas.html

Some of my favorite are things where MyQL accepts values it shouldn't and it doesn't throw an error. For example you can insert a 0 into a date field, 30000000000 into an in column (it will just ignore the higher order bits.

MySQL is OK for quick and dirty, but it will always be dirty. If you want MySQL to be decent:

1) Set it up with InnoDB and make that the default table type. MyISAM should only be used for data warehouse tpye applications where you are doing a lot of IO and its OK for the DB to be down for hours while you recover your corrupted MyISAM tables.
2) Set the strict sql mode in the my.cnf. I don't remember exactly what the parameter name is, but you want MyQL to throw an error if you throw stupid values at it. Otherwise it will accept wacky values and you'll end up debugging it later.
3) Set the default character set to UTF-8 if you can. This can be a bear but its worth it to be able to handle foreign characters.
4) Avoid the fancy "features" if you can. The old features still have unresolved bugs and it isn't going to get any better with more and more storage engines going in.
5) Monitor the performance constantly and be prepared to partition your data. Scale out isn't always as easy as it sounds.